Chapter dzǶ: Tautologies in Economics and the Natural Sciences ȁȅȄErnst Mayr (ȀȈȇȁ, p.ȁȂ) rejects seeing “science merely as an accumu-
lation of facts.” In biology, “most major progress was made by the intro-
duction of new concepts, or the improvement of existing concepts. Our
understanding of the world is achieved more effectively by conceptual
improvements than by the discovery of new facts, even though the two
are not mutually exclusive.”
A.A. Zinov’ev emphasizes how suitably chosen definitions, terms, and
symbols render scientific discussion more intuitively obvious, compact,
and convenient. In their absence, “the record of knowledge and operating
with it become practically impossible. Ļe search for the most convenient
forms of abbreviation represents one of the most important tasks in the
construction of scientific language in general” (ȀȈȇȂ, pp.Ȁȃ–ȀȄ).
What ultimately counts in an empirical science, says Daniel Haus-
man (ȀȈȈȁ, p.ȁȈȇ) is identifying regularities in the world. “But science
does not proceed by spotting correlations among well-known observable
properties of things. Ļe construction of new concepts, of new ways of
classifying and describing phenomena is an equally crucial part of science.
Such conceptual work has been prominent in economics.”
ŐődžŚŕŠŕśŚş ōŚŐ őřŜŕŞŕŏş: ţōŘŞōş’ş Řōţ ōŚŐ
ŠŔő őŝšōŠŕśŚ śŒ őŤŏŔōŚœő
Two notable tautologies in economics illustrate certain relations between
definitional truths and empirical reality. Walras’s Law illuminates interre-
lations among supplies of and demands for goods, services, securities, and
money and among their supply/demand imbalances. Ļe Law emphasizes
that no one thing or group of things can be in excess supply or excess
demand by itself. It thereby helps focus attention on the role in macroeco-
nomic disorder of a distinctively functioning object of exchange—money.
Similarly, it emphasizes that no change in tastes or technology can affect
the supply or demand of a single thing alone; at least two things must be
involved.
In one formulation, Walras’s Law states that if a general-equilibrium
equation system specifies equality between quantities supplied and de-
manded of all goods in the economy but one, then an equation for the
one remaining good would be otiose. Instead of being mathematically
independent, it would merely duplicate information already contained in
the other equations. Supply-demand equilibrium for all goods but one
already implies equilibrium for whatever the remaining good may be.